阅读下列材料:1x2=3分之1(1x2x3-0x1x2),2x3=3分之1(2x3x4-1x2x3),3x4=3分之1(3x4x5-2x3x4),阅读下列材料:1x2=3分之1(1x2x3-0x1x2),2x3=3分之1(2x3x4-1x2x3),3x4=3分之1(3x4x5-2x3x4),由以上三个等式相加,
来源:学生作业帮助网 编辑:作业帮 时间:2024/07/07 10:24:32
![阅读下列材料:1x2=3分之1(1x2x3-0x1x2),2x3=3分之1(2x3x4-1x2x3),3x4=3分之1(3x4x5-2x3x4),阅读下列材料:1x2=3分之1(1x2x3-0x1x2),2x3=3分之1(2x3x4-1x2x3),3x4=3分之1(3x4x5-2x3x4),由以上三个等式相加,](/uploads/image/z/614900-20-0.jpg?t=%E9%98%85%E8%AF%BB%E4%B8%8B%E5%88%97%E6%9D%90%E6%96%99%EF%BC%9A1x2%3D3%E5%88%86%E4%B9%8B1%EF%BC%881x2x3-0x1x2%EF%BC%89%2C2x3%3D3%E5%88%86%E4%B9%8B1%EF%BC%882x3x4-1x2x3%EF%BC%89%2C3x4%3D3%E5%88%86%E4%B9%8B1%EF%BC%883x4x5-2x3x4%EF%BC%89%2C%E9%98%85%E8%AF%BB%E4%B8%8B%E5%88%97%E6%9D%90%E6%96%99%EF%BC%9A1x2%3D3%E5%88%86%E4%B9%8B1%EF%BC%881x2x3-0x1x2%EF%BC%89%2C2x3%3D3%E5%88%86%E4%B9%8B1%EF%BC%882x3x4-1x2x3%EF%BC%89%2C3x4%3D3%E5%88%86%E4%B9%8B1%EF%BC%883x4x5-2x3x4%EF%BC%89%2C%E7%94%B1%E4%BB%A5%E4%B8%8A%E4%B8%89%E4%B8%AA%E7%AD%89%E5%BC%8F%E7%9B%B8%E5%8A%A0%2C)
阅读下列材料:1x2=3分之1(1x2x3-0x1x2),2x3=3分之1(2x3x4-1x2x3),3x4=3分之1(3x4x5-2x3x4),阅读下列材料:1x2=3分之1(1x2x3-0x1x2),2x3=3分之1(2x3x4-1x2x3),3x4=3分之1(3x4x5-2x3x4),由以上三个等式相加,
阅读下列材料:1x2=3分之1(1x2x3-0x1x2),2x3=3分之1(2x3x4-1x2x3),3x4=3分之1(3x4x5-2x3x4),
阅读下列材料:
1x2=3分之1(1x2x3-0x1x2),
2x3=3分之1(2x3x4-1x2x3),
3x4=3分之1(3x4x5-2x3x4),
由以上三个等式相加,可得
1x2+2x3+3x4+3分之1x3x4x5=20
读完以上材料,请你计算下列各题:
(1)1x2+2x3+3x4+…+10x11(写出过程)
(2)1x2+2x3+3x4+…+n x(n+1);
(3)1x2x3+2x3x4+3x4x5+…+7x8x9(写出过程)
阅读下列材料:1x2=3分之1(1x2x3-0x1x2),2x3=3分之1(2x3x4-1x2x3),3x4=3分之1(3x4x5-2x3x4),阅读下列材料:1x2=3分之1(1x2x3-0x1x2),2x3=3分之1(2x3x4-1x2x3),3x4=3分之1(3x4x5-2x3x4),由以上三个等式相加,
(1)1x2+2x3+3x4+…+10x11
=1*10*11*12/3
=440
(2)原式=n(n+1)(n+2)/3
(3)1x2x3+2x3x4+3x4x5+…+7x8x9
=1x2x3×4/4-0×1×2×3/4+2x3x4×5/4-1×2×3×4/4…+7x8x9×10/4-6×7×8×9/4
=7×8×9×10/4
=1260
1)1x2+2x3+3x4+…+10x11
=1*10*11*12/3
=440
(2)原式=n(n+1)(n+2)/3
(3)1x2x3+2x3x4+3x4x5+…+7x8x9
=1x2x3×4/4-0×1×2×3/4+2x3x4×5/4-1×2×3×4/4…+7x8x9×10/4-6×7×8×9/4
=7×8×9×10/4
=1260